Bearing capacity of bolted-mortar infill connections in bamboo and yield model formulation

Abstract

Bolted-mortar infill connections in bamboo structures are one of the most challenging aspects of the design and construction of these structures, due to the uncertainty in the evaluation of the connection strength. The shape of bamboo cross-sections (round, hollow and tapered) and the interaction between bamboo, mortar infill, and steel bolts or dowels are not clearly understood. Therefore, the main objective of this research was to develop an analytical method to estimate the strength of Bolted mortar infill (BMI) bamboo connections, based on the modified yield model theory (EYM). The proposed model consists of 5 controlling yield modes used to predict a BMI bamboo connection behaviour under load applied parallel and perpendicular to the fiber direction, based on the strength and geometry of materials. To validate the proposed model, a comprehensive experimental program that consisted of 112 tests for evaluating dowel-bearing strength on the Guadua bamboo, 126 test for determining bearing strength of the mortar filling, 61 test for evaluating bolt bending yield strength and 70 BMI connections were performed for 10 different configurations of dowel diameter and load angle direction. After calibration procedures, the model adequately predicted the connection strength for the different connection configurations with an average difference between the predicted and tested and Colombian National Code (NSR-10) values of 15.7% and 11.6%, respectively. In general, the predicted values of the proposed model, underestimate the connections capacity. This research aims to improve the design procedures and national regulations for BMI connections of Guadua Angustifolia Kunth and other bamboo species.